1. Technical Field
This invention relates to a method for applying radio frequency identification (RFID) tags to products, cases, pallets, or any other item, and specifically for applying and verifying RFID tags, and assigning and accounting for numbers and other product and product-related information such as serial numbers, global trade identification numbers (GTINs), electronic product codes (EPCs), and stock keeping units (SKUs).
2. Description of Related Art
The present invention generally relates to radio frequency identification (RFID) tags, and more particularly to methods to apply RFID tags to items and manage the information associated there with. Such methods may be used in any environment, but particularly are advantageously used in supply chain and warehouse management environments.
FIG. 1 shows a typical RFID tag according to the prior art. With reference to FIG. 1, a typical RFID tag is comprised of an antenna 102, a microchip 104, and optionally an adhesive strip 106 to facilitate the placement of the RFID tag on an object. Optionally, on one side of an adhesive strip 106, human readable and other printed information may be affixed to the RFID tag. Many RFID tags and devices have the potential to carry a large quantity of information in contrast to conventional bar codes whose data capacity is limited. RFID tags may be read faster and at relatively larger distances, can be rewritten and updated repeatedly and easily, do not require line-of-sight reading, and can contain encrypted data or locked data. RFID tags can be easily tracked. By keeping RFID and allied data on a network resource such as a server, a service provider could enable stores and warehouses to use portable scanners to check the history of a tagged product. Retailers could check for authenticity or theft, as well as monitor product trends by tracking items. RFID tags may be programmable and may also include sensors that can record in the tag various environmental factors such as the amount of time a container was held at a given temperature.
In the manufacturing, shipping, supply chain, warehouse, and retail industries, RFID tags can be attached to one or more objects (e.g., containers, packages, products) for purposes of providing information about the objects. RFID tags are also referred to as RFID transponders. Such RFID tags can provide an RFID interrogator or reader with data that can directly or indirectly provide the information about the corresponding objects. A reading pulse of RF energy interrogates passive tags as the tags are brought near to the reader. The object information may be stored and retrieved using any number of techniques and data formats. The information may be part of the RFID response code or alternately maintained in a database external to the RFID interrogator with a correlation to the RFID identification sent by the RFID tag in response to an interrogation signal.
One problem often encountered with the use of RFID tags on multiple items stacked in a tote or on a pallet is that some tags escape interrogation and the information is not read from certain tags. Specifically, RF waves from an interrogator may not adequately reach the antenna of the RFID tag. A passive RFID tag ordinarily creates power from these RF waves and uses them to energize the circuits of the RFID chip. The chip in the RFID tag then sends information back to the reader.
FIG. 2 shows a typical RFID tag attachment process at a manufacturing, shipping or warehouse facility wherein certain problems may originate. With reference to FIG. 2, as a product 204 travels down a conveyor 206, a worker or machine 208 affixes a functioning RFID tag 202A to it. A product 204 may be an individually packaged product, tote, crate, box, or other object.
As products 204 are stacked onto a pallet for further handling and shipping, some RFID tags are broken. In one study, the failure rate of applying RFID tags to products was one percent. Further, some RFID tags are placed in a poor location relative to the container and may be unreadable by an RFID tag interrogator. For example, an RFID tag 202C could be inadvertently placed in the middle of a side of a container 204 wherein a large metal or liquid object 212 resides. Such placement could at least partially obstruct and/or interfere with an interrogation signal emitted by the RF interrogator 216 and/or interfere with a response signal emitted by the RFID tag 202C. An RF interrogator 216 may be built near a door or gateway so as to scan and read RFID tags 202 as they leave or arrive as part of a shipment. Such placement may be non-ideal and may further contribute to failing to detect some RFID tags.
Alternatively, problems may arise when some containers carrying RFID tags stacked in such a manner that the tags are in a relatively poor location within the shipping container. For example, with are reference to FIG. 2, a product 204 having an RFID tag 202B could be stacked such that the RFID tag 202B is located toward the center of the pallet. A box placed in an adjacent space 210 could obstruct the functioning of the RFID tag 202B. In these situations, when the pallet 214 loaded with products 204 passes near interrogators 216 for scanning, certain of the RFID tags 202B, 202C may not function correctly. This translates to “lost” containers and a manual correction would have to be performed.
In the prior art, serialized numbers may be assigned to specific products or RFID tags before the RFID tags are encoded, affixed, and verified by interrogation. In such a case, additional effort would be wasted in tracking down serialized numbers assigned to non-functioning RFID tags or to products bearing non-functioning RFID tags.
Ideally, application and verification of RFID tags to products, stacked containers, and shipments would most easily be incorporated into the manufacturing and packaging processes. However, many manufacturing and packaging facilities do not incorporate the use of RFID tags into these processes.
Accordingly, a need exists for a process or method which allows either a machine or operators 224 to optimally apply RFID tags to products 204 and stack products 204 onto a pallet 214 or other container according to an optimal or desired arrangement of the RFID tags 202 relative to the exterior of the pallet 214. Further, a need exists for an efficient process and method to assign codes or other information to verifiably working RFID tags. A need exists to reliably and consistently place RFID tags onto items such that the RFID tags are optimally placed for a given arrangement of products in a container. A need exists to reliably and consistently stack items onto a pallet or other container whereby a sufficient number of products in such container may be interrogated and identified and thereby provide an improved means to identify the entire container and all products stacked therein.
Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.